1. Technical Field
The invention generally relates to chairs, particularly to elbows of chairs.
2. Related Art
General chairs are usually equipped with fixed elbows whose height and position can not be adjusted for matching various users. Latterly, chairs with rotary elbows appear in the market. The rotary elbows allow horizontal rotation for satisfying various requirements of users. Such an elbow can provide better support to users to avoid aches and pains of hands and ill posture of bodies. However, because conventional rotary elbows adopt a single rotating shaft, the elongated elbows rotating around a single bearing can not maintain a stably planar rotation, and the bearing is easily damaged by unbalanced pressure.